Question

what is the value of x in trapezoid abcd?
○ x=15
○ x=20
○ x=45
○ x=60

Explanation:

Step1: Use the property of isosceles trapezoid

In an isosceles trapezoid, consecutive angles between the bases are supplementary. So, \(3x + 9x=180\).

Step2: Solve the equation

Combine like - terms: \(12x = 180\). Then divide both sides by 12: \(x=\frac{180}{12}=15\).

Answer:

\(x = 15\) (the first option)